Source of standard: North American Association of Central Cancer Registriesexternal icon

Source item name: Grade

Source item number: 440external icon

This variable indicates the grade or degree of differentiation of the primary tumor being reported. For lymphomas and leukemias, this field also is used to indicate T-, B-, Null-, or NK-cell origin.

Considerations for Use

  • Data are available for cases diagnosed in 2001 through 2017. This data item was not collected for cases diagnosed in 2018.
  • The practice of grading varies greatly among pathologists throughout the world, and many malignant tumors are not graded routinely. Since different grading systems may be used, review the SEER site-specific modulesexternal icon and the FORDS manualexternal icon that corresponds with the diagnosis year. Each module has an abstracting, coding, and staging section, which has a morphology and grading subsection. Some modules, but not all, contain notes about the grading system that may have been used. Currently, there is no variable to differentiate a specific grading system from another one if more than two grading systems are mentioned.
  • Diagnostic practices also influence coding practices. For example, preliminary analysis of tumor grade for prostate cancer showed an increase in the proportion of higher grades from 2002 to 2003. Additional review showed this increase to be artificial, as the International Society of Urologic Pathologists, in conjunction with the World Health Organization (WHO), had made a series of recommendations for modification of the Gleason grading system to reflect contemporary knowledge, alleviate uncertainty, and promote uniformity in its application. One recommendation was for pathologists to report all higher tertiary grade components of the tumor as part of the Gleason score. Another recommendation was made for reporting of any higher-grade cancer, no matter how small quantitatively.
  • The percentage of cases with a known grade varies by primary cancer site. Rules for coding the tumor grade differ for some primary sites. As a result, it may be appropriate to have a tumor grade coded as “9 – unknown.”
  • For brain tumor cases diagnosed from 2011 to 2017, cancer registries were required to report the WHO grade classification. Please see the variable description CS site-specific factor 1 for more information on this brain-specific grade classification.

Note: This frequency table is restricted to cancers diagnosed during 2001 to 2017.